Identification, Structural Characterization and Gene Expression Analysis of Members of the Nuclear Factor-Y Family in Chickpea (Cicer arietinum L.) under Dehydration and Abscisic Acid Treatments

Genome-wide identification of NF-Y gene family in maize (Zea mays L.) and the positive role of ZmNF-YC12 in drought resistance and recovery ability

Nuclear factor Y (NF-Y) genes play important roles in many biological processes, such as leaf growth, nitrogen nutrition, and drought resistance. However, the biological functions of these transcription factor family members have not been systematically analyzed in maize. In the present study, a total of 52 ZmNF-Y genes were identified and classified into three groups in the maize genome. An analysis of the evolutionary relationship, gene structure, and conserved motifs of these genes supports the evolutionary conservation of NF-Y family genes in maize. The tissue expression profiles based on RNA-seq data showed that all genes apart from ZmNF-Y16, ZmNF-YC15, and ZmNF-YC17 were expressed in different maize tissues. A weighted correlation network analysis was conducted and a gene co expression network method was used to analyze the transcriptome sequencing results; six core genes responding to drought and rewatering were identified. A real time fluorescence quantitative analysis showed that these six genes responded to high temperature, drought, high salt, and abscisic acid (ABA) treatments, and subsequent restoration to normal levels. ZmNF-YC12 was highly induced by drought and rewatering treatments. The ZmNF-YC12 protein was localized in the nucleus, and the Gal4-LexA/UAS system and a transactivation analysis demonstrated that ZmNF-YC12 in maize (Zea mays L.) is a transcriptional activator that regulates drought resistance and recovery ability. Silencing ZmNF-YC12 reduced net photosynthesis, chlorophyll content, antioxidant (superoxide dismutase, catalase, peroxidase and ascorbate peroxidase) system activation, and soluble protein and proline contents; it increased the malondialdehyde content, the relative water content, and the water loss rate, which weakened drought resistance and the recoverability of maize. These results provide insights into understanding the evolution of ZmNF-Y family genes in maize and their potential roles in genetic improvement. Our work provides a foundation for subsequent functional studies of the NF-Y gene family and provides deep insights into the role of the ZmNF-YC12 regulatory network in controlling drought resistance and the recoverability of maize.

Crucial Abiotic Stress Regulatory Network of NF-Y Transcription Factor in Plants

Nuclear Factor-Y (NF-Y), composed of three subunits NF-YA, NF-YB and NF-YC, exists in most of the eukaryotes and is relatively conservative in evolution. As compared to animals and fungi, the number of NF-Y subunits has significantly expanded in higher plants. The NF-Y complex regulates the expression of target genes by directly binding the promoter CCAAT box or by physical interaction and mediating the binding of a transcriptional activator or inhibitor. NF-Y plays an important role at various stages of plant growth and development, especially in response to stress, which attracted many researchers to explore. Herein, we have reviewed the structural characteristics and mechanism of function of NF-Y subunits, summarized the latest research on NF-Y involved in the response to abiotic stresses, including drought, salt, nutrient and temperature, and elaborated the critical role of NF-Y in these different abiotic stresses. Based on the summary above, we have prospected the potential research on NF-Y in response to plant abiotic stresses and discussed the difficulties that may be faced in order to provide a reference for the in-depth analysis of the function of NF-Y transcription factors and an in-depth study of plant responses to abiotic stress.

Overexpression of an NF-YC2 gene confers alkali tolerance to transgenic alfalfa (Medicago sativa L.)

Alkaline stress severely limits plant growth and yield worldwide. NF-YC transcription factors (TFs) respond to abiotic stress by activating gene expression. However, the biological function of NF-YC TFs in alfalfa (Medicago sativa L.) is not clear. In our study, an NF-YC2 gene was identified and transgenic plants were obtained by constructing overexpression vector and cotyledon node transformation system in alfalfa. The open reading frame of MsNF-YC2 is 879 bp with 32.4 kDa molecular mass. MsNF-YC2 showed tissue expression specificity and was induced by a variety of abiotic stresses including drought, salt, and alkali stress in alfalfa. Under alkali stress treatment, transgenic plants exhibited higher levels of antioxidant enzyme activities and proline (Pro), correlating with a lower levels of hydrogen peroxide (H₂O₂), superoxide anion (O₂ ^-) compared with wild-type (WT) plants. Transcriptomic results showed that overexpression of MsNF-YC2 regulated the expression of phytohormone signal transduction and photosynthesis-related genes under normal and alkaline stress treatments. These results suggest that the MsNF-YC2 gene plays crucial role enhance alkali adaptation abilities in alfalfa.

Insights into the gene and protein structures of the CaSWEET family members in chickpea (Cicer arietinum), and their gene expression patterns in different organs under various stress and abscisic acid treatments

'Sugars Will Eventually be Exported Transporters' (SWEETs) are a group of sugar transporters that play crucial roles in various biological processes, particularly plant stress responses. However, no information is available yet for the CaSWEET family in chickpea. Here, we identified all putative CaSWEET members in chickpea, and obtained their major characteristics, including physicochemical patterns, chromosomal distribution, subcellular localization, gene organization, conserved motifs and three-dimensional protein structures. Subsequently, we explored available transcriptome data to compare spatiotemporal transcript abundance of CaSWEET genes in various major organs. Finally, we studied the changes in their transcript levels in leaves and/or roots following dehydration and exogenous abscisic acid treatments using RT-qPCR to obtain valuable information underlying their potential roles in chickpea responses to water-stress conditions. Our results provide the first insights into the characteristics of the CaSWEET family members and a foundation for further functional characterizations of selected candidate genes for genetic engineering of chickpea.

Genome-wide identification and expression analysis of the GRAS gene family in response to drought stress in chickpea (Cicer arietinum L.)

The GRAS (gibberellic acid insensitive, repressor of GAI and scarecrow) transcription factors (TFs) regulate diverse biological processes involved in plant growth and development. These TFs are also known to regulate gene expression in response to various abiotic stress factors like cold, drought, etc. In chickpea one of the most devastating abiotic stress factors is terminal drought. The GRAS TF family has not been characterized in chickpea (Cicer arietinum L.) until now. In this study, we report 46 GRAS TF genes (CaGRAS genes) in the chickpea genome. The CaGRAS proteins were categorized into nine subfamilies based on their phylogenetic relationship with known GRAS members of Arabidopsis and soybean. The PAT subfamily was the largest consisting of ten CaGRAS members whereas the LAS subfamily was the smallest with only one member. Gene duplication analysis revealed that segmental duplication was the primary reason for the expansion of this gene family within the chickpea genome. The gene expression levels of CaGRAS genes were analysed using two different chickpea varieties contrasting for drought tolerance trait, i.e., ICC 4958 (drought tolerant) and ICC 1882 (drought sensitive). On exposure to drought stress, the two chickpea genotypes, exhibited differential drought response, which was quantified and estimated in terms of differences in leaf relative water content (RWC). The well-watered or control plants of the drought tolerant variety were able to maintain a higher leaf RWC by the end of the drought stress period, whereas the control plants of the drought sensitive variety continued to show a decline in leaf RWC. The two genotypes also differed in their root morphologies, under well-watered and drought stress conditions. The gene expression analysis revealed a potential role of PAT, SCR, SCL3 and SHR GRAS members in the regulation of differential response to drought, in the root tissues, for both the genotypes. CaGRAS 12 (SCR) was identified as a drought-responsive GRAS TF gene, which could serve as a potential candidate gene for utilization in developing chickpea varieties with improved drought tolerance. This study demonstrates the drought-responsive expression of CaGRAS genes in chickpea and also describes the morpho-physiological response of chickpea plants to drought stress conditions.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-03104-z.

Genome-Wide Analysis and Expression Profile of Nuclear Factor Y (NF-Y) Gene Family in Z. jujuba

Nuclear factor-Y (NF-Y) is an important transcription factor in the plant species, which potentially provides a higher level of functional diversity including for abiotic stress tolerance. The genome-wide study and expression analysis of NF-Y gene family in Ziziphus, an elite abiotic stress-tolerant species, assist bioprospecting of genes. Here, a total of 32 NF-Y (8 NF-YA, 15 NF-YB, and 9 NF-YC) genes were identified in genome-wide search of Z. jujuba genome. Physicochemical properties, cellular localization, gene structure, chromosomal location, and protein motifs were analyzed for structural and functional understanding. Identified 12 NF-Ys were responsible for the expansion of NF-Y gene family by tandem duplication in Z. jujuba. Phylogenetic and comparative physical mapping of Z. jujuba NF-Ys with its orthologs illustrated evolutionary and functional insights into NF-Y gene family. A total of 45 perfect microsatellites (20bp to 40bp) were extracted across the ZjNF-Y genes. The promoter and gene ontology study suggested that Z. jujuba NF-Y gene family is functionally diverse and could play a wide-ranging role in plant abiotic stress, development, and cellular processes. An expression study revealed that large numbers of the NF-Ys are differentially expressed in response to drought and salinity. The total 15 and 18 ZjNF-Y genes that are upregulated under drought and salinity stress, respectively, are the potential candidates for further functional analysis for development of climate-resilient crops. The present study established a base for understanding the role of NF-Ys in Z. jujuba under abiotic stress conditions and paved a way for further research.

Genome-Wide Analysis of NF-Y Genes in Potato and Functional Identification of StNF-YC9 in Drought Tolerance

The nuclear factor Y (NF-Y) family is comprised of transcription factors that have been implicated in multiple plant biological processes. However, little is known about this family in potato. In the present study, a total of 41 StNF-Y genes were identified in the potato genome. In addition, the phylogenetic, gene structure, motif, and chromosomal location of this family were analyzed. The tissue expression profiles based on RNA-seq data showed that 27 StNF-Y genes had tissue-specific expression, while the remaining 14 had low expression in all tissues. Publicly available transcriptomics data from various abiotic stresses revealed several stress-responsive StNF-Y genes, which were further verified via quantitative real-time polymerase chain reaction experiments. Furthermore, the StNF-YC9 gene was highly induced by dehydration and drought treatments. StNF-YC9 protein was mainly localized in the nucleus and cytoplasmic membrane. Overexpressing StNF-YC9 potato lines (OxStNF-YC9) had significantly increased in root length and exhibited stronger stomatal closure in potato treated by polyethylene-glycol and abscisic acid. In addition, OxStNF-YC9 lines had higher photosynthetic rates and decreased water loss under short-term drought stress compared to wild-type plants. During long-term drought stress, OxStNF-YC9 lines had higher proline levels, lower malondialdehyde content, and increased activity of several antioxidant enzymes, including superoxide dismutase, catalase, and peroxidase. This study increased our understanding of the StNF-Y gene and suggested that StNF-YC9 played an important role in drought tolerance by increased the photosynthesis rate, antioxidant enzyme activity, and proline accumulation coupled to lowered malondialdehyde accumulation in potato.

Genomic Organization, Phylogenetic Comparison, and Differential Expression of the Nuclear Factor-Y Gene Family in Apple (Malus Domestica)

The nuclear factor Y (NF-Y) as a transcription factor plays an important role in plants growth and development, and response to stress. However, few genome-wide analyzes and functional research of the NF-Y family has been undertaken in apple (Malus domestica Borkh.) so far. In this study, we comprehensively identified the 43 MdNF-Y genes in apple, which dispersedly distributed among the three subgroups based on their sequence alignment analysis, including 11 MdNF-YAs, 22 MdNF-YBs and 10 MdNF-YCs. The members in the same subgroups had similar evolution relationships, gene structures, and conserved motifs. The gene duplication analysis suggested that all the genes were dispersed followed by 27 segmental duplication. Moreover, based on synteny analysis of MdNF-Ys with eight plant species results suggested that some ortholog genes were preserved during the evolution of these species. Cis-element analysis showed potential functions of MdNF-Ys in apple growth and development and responded to abiotic stress. Furthermore, the interaction among MdNF-Ys protein were investigated in yeast two-hybrid assays. The expression patterns of MdNF-Ys in tissue-specific response reveled divergence and might play important role in apple growth and development. Subsequently, whole MdNF-Y genes family was carried out for RT-PCR in response to five abiotic stress (ABA, drought, heat, cold, and salinity) to identify their expression patterns. Taken together, our study will provide a foundation for the further study to the molecular mechanism of apple in growing development and response to abiotic stresses.

Genome-wide identification of NF-YA gene family in cotton and the positive role of GhNF-YA10 and GhNF-YA23 in salt tolerance

Nuclear factor YA (NF-YA) genes play important roles in many biological processes, such as leaf growth, nitrogen nutrition, drought resistance, and salt stress. The functions of NF-YA genes in cotton have not been elucidated. The current study identified a total of 16, 16, 31, and 29 genes from Gossypium raimondii, G. arboretum, G. barbadense, and G. hirsutum, respectively. The NF-YA genes in cotton were phylogenetically classified into 4 groups. Analysis of gene structure, conserved motifs and multiple sequence alignments supported the evolutionary conservation of NF-YA family genes in cotton. Analysis of the expression patterns of GhNF-YAs in cotton suggested that GhNF-YAs play important roles in plant growth, development, and stress responses. The quantitative real-time PCR (qRT-PCR) validation of selected genes suggested that GhNF-YA genes are induced in response to salt, drought, ABA, and MeJA treatments. GhNF-YA genes may regulate salt and drought stress via the ABA or MeJA pathway. Silencing of GhNF-YA10 and GhNF-YA23 significantly reduced the salt tolerance of cotton seedlings, indicating that these genes participate in the regulation of the response of cotton to salt stress. These results establish a foundation for subsequent functional studies of the NF-YA gene family in cotton.

Identification, expression, and putative target gene analysis of nuclear factor-Y (NF-Y) transcription factors in tea plant (Camellia sinensis)

Genome-wide identification and characterization of nuclear factor-Y family in tea plants, and their expression profiles and putative targets provide the basis for further elucidation of their biological functions. The nuclear factor-Y (NF-Y) transcription factors (TFs) are crucial regulators of plant growth and physiology. However, the NF-Y TFs in tea plant (Camellia sinensis) have not yet been elucidated, and its biological functions, especially the putative target genes within the genome range, are still unclear. In this study, we identified 35 CsNF-Y encoding genes in the tea plant genome, including 10 CsNF-YAs, 15 CsNF-YBs and 10 CsNF-YCs. Their conserved domains and motifs, phylogeny, duplication event, gene structure, and promoter were subsequently analyzed. Tissue expression analysis revealed that CsNF-Ys exhibited three distinct expression patterns in eight tea tree tissues, among which CsNF-YAs were moderately expressed. Drought and abscisic acid (ABA) treatment indicated that CsNF-YAs may have a greater impact than other subunit members. Furthermore, through the genome-wide investigation of the presence of the CCAAT box, we found that CsNF-Ys may participate in the development of tea plants by regulating target genes of multiple physiological pathways, including photosynthesis, chlorophyll metabolism, fatty acid biosynthesis, and amino acid metabolism pathways. Our findings will contribute to the functional analysis of NF-Y genes in woody plants and the cultivation of high-quality tea plant cultivars.

Genome-wide identification and expression profile analysis of nuclear factor Y family genes in Sorghum bicolor L. (Moench)

Members of the plant Heme Activator Protein (HAP) or NUCLEAR FACTOR Y (NF-Y) are trimeric transcription factor complexes composed of the NF-YA, NF-YB and NF-YC subfamilies. They bind to the CCAAT box in the promoter regions of the target genes and regulate gene expressions. Plant NF-Ys were reported to be involved in adaptation to several abiotic stresses as well as in development. In silico analysis of Sorghum bicolor genome resulted in the identification of a total of 42 NF-Y genes, among which 8 code for the SbNF-YA, 19 for SbNF-YB and 15 for the SbNF-YC subunits. Analysis was also performed to characterize gene structures, chromosomal distribution, duplication status, protein subcellular localizations, conserved motifs, ancestral protein sequences, miRNAs and phylogenetic tree construction. Phylogenetic relationships and ortholog predictions displayed that sorghum has additional NF-YB genes with unknown functions in comparison with Arabidopsis. Analysis of promoters revealed that they harbour many stress-related cis-elements like ABRE and HSE, but surprisingly, DRE and MYB elements were not detected in any of the subfamilies. SbNF-YA1, 2, and 6 were found upregulated under 200 mM salt and 200 mM mannitol stresses. While NF-YA7 appeared associated with high temperature (40°C) stress, NF-YA8 was triggered by both cold (4°C) and high temperature stresses. Among NF-YB genes, 7, 12, 15, and 16 were induced under multiple stress conditions such as salt, mannitol, ABA, cold and high temperatures. Likewise, NF-YC 6, 11, 12, 14, and 15 were enhanced significantly in a tissue specific manner under multiple abiotic stress conditions. Majority of the mannitol (drought)-inducible genes were also induced by salt, high temperature stresses and ABA. Few of the high temperature stress-induced genes are also induced by cold stress (NF-YA2, 4, 6, 8, NF-YB2, 7, 10, 11, 12, 14, 16, 17, NF-YC4, 6, 12, and 13) thus suggesting a cross talk among them. This work paves the way for investigating the roles of diverse sorghum NF-Y proteins during abiotic stress responses and provides an insight into the evolution of diverse NF-Y members.

Genome-wide analysis of the NF-Y gene family in peach (Prunus persica L.)

Background

Nuclear Factor Y (NF-Y) is a heterotrimeric complex composed of three unique subunits: NF-YA, NF-YB, and NF-YC. The NF-Y transcription factor complex binds to the CCAAT box of eukaryotic promoters, playing a vital role in various biological processes in plants. However, the NF-Y gene family has not yet been reported from the peach genome. The current study identified and classified candidate peach NF-Y genes for further functional analysis of this family.

Results

The current study identified 24 Nuclear Factor Y (NF-Y) transcription factor subunits (6 NF-YA, 12 NF-YB, and 6 NF-YC subunits) in peach. These NF-Y subunits were described with respect to basic physicochemical characteristics, chromosome locations, gene structures, and conserved domains. Based on an analysis of the phylogenetic relationships among peach NF-Ys, six pairs of paralogous NF-Ys were detected. The expansion of the peach NF-Y family occurred by segmental and tandem duplication. Phylogenetic gene synteny of NF-Y proteins was observed between peach and Arabidopsis, and five pairs of paralogous NF-Y proteins from peach and Arabidopsis were identified. Twenty-four peach NF-Ys displayed a diversity of tissue expression patterns. In addition, drought-responsive cis-elements were observed in peach NF-Y promoters, and 9 peach NF-Y genes were shown to distinctly increase their transcript abundances under drought stress.

Conclusions

This study identified 24 NF-Y genes in the peach genome and analysed their properties at different levels, providing a foundation for researchers to understand this gene family in peach. The up-regulation of 9 NF-Y genes under drought stress indicates that they can serve as candidate functional genes to further study drought resistance in peach.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5968-7) contains supplementary material, which is available to authorized users.